This invention relates to the fields of motion picture and video production, and more particularly to apparatus and methods for motorizing and remotely controlling, using a digitally controlled microprocessor, existing manually operated geared heads for positioning motion picture and electronic medium (such as video) cameras.
Prior art geared heads for positioning motion picture and electronic medium cameras are usually operated manually. When the cameraman needs to move the camera right to left (known in the art as xe2x80x9cpanningxe2x80x9d the camera) or up and down (known in the art as xe2x80x9ctiltingxe2x80x9d the camera), the operator will rotate two hand wheels, each controlling an axis. For example, if the cameraman needs to make a 180 degree pan, he has to physically travel 180 degrees behind the camera in an arc with the camera to view the shot through the viewing system.
Referring now to FIG. 1, there is shown therein a typical prior art geared head system 11. The illustrated geared head system 11 is sold under the trademark ARRIHEAD 2, available from Arri, Inc. However, it is merely representative, and any similar type of geared head assembly could alternatively be referenced. The geared head system 11 includes a camera platform 13, which is capable of adjustment in at least two axes, namely pan and tilt. A tilt handwheel 15 and a pan handwheel 17 are provided for use by the camera operator when it is desired to pan and/or tilt the camera (not shown) mounted on the platform 13. The camera platform 13 is disposed on a gearhead housing 19, within which reside a plurality of interengaged gears for selectively driving the camera platform, and thus the camera mounted thereon, through a predetermined range of motion in the pan and tilt axes. The gearhead housing 19 is supported by a plurality of legs 21.
Thus, in operation, the camera operator is stationed behind the gearhead housing 19, in position to actuate the two hand wheels 15 and 17, and to view the scene through the viewfinder of the camera (not shown). To pan or tilt the camera, the hand wheels 15 and 17 are selectively rotated. Since the hand wheels 15 and 17 are drivingly connected to the interengaged gears via a manual tilt gear drive interface and a manual pan gear drive interface, respectively, rotation of the hand wheels 15 and 17 functions to drive the gears within the gearhead housing 19, which in turn are drivingly engaged with the camera platform 13. In other words, the hand wheels 15 and 17 are mechanically linked to the platform 13 so that a ratio of turns will be converted into movement, through the gearhead, in the tilt axis and the pan axis, respectively. In some embodiments (not shown), a third hand wheel or motor is provided which rotates the camera on a roll axis. There is no ability to provide predetermined fixed stops in pan, and in tilt, only the end of the permitted travel arc provides a hard stop. No intermediate stops may be selected.
Most existing geared heads have three mechanical gear ratios which enable the camera operator to choose the rate at which he would like to move the photographic device. Unfortunately, this limited selection of travel speeds can be very restrictive during a shoot.
With a conventional geared head, it is very difficult to move the camera rapidly and stop on a precise mark. Generally, since the operator cannot see beyond the viewing system when the final mark will be approaching, it is possible to either go beyond the final mark or to fail to reach the final mark. Geared heads for motion picture and electronic medium cameras were designed to assist the camera operator""s ability to pan or tilt the camera from point A to point B with a greater degree of accuracy than was previously possible, in order to accommodate the ever more complex shots required in an increasingly sophisticated and demanding industry, but their present limitations continue to frustrate both camera operators and directors.
Presently available geared heads have virtually infinite panning ability, but are generally restricted to +/xe2x88x92 approximately 30 degrees in tilt. It is possible, therefore, for the operator to reach a hard mechanical stop on the tilt axis during photography, which is unacceptable in most cases.
Additionally, because present motion picture geared heads are operated manually, it is possible to move the camera the same way multiple times, but never to replicate a previous camera move exactly.
Still another problem with existing geared head assemblies is the necessity for the camera operator to be positioned directly behind the assembly. Often, the camera must be placed in a relatively hazardous orientation in order to obtain an acceptable shot, and this entails danger and inconvenience to the operator. Although remote controlled cameras are presently available for such occasions, they are generally very expensive and relatively complex, and are not adaptable to typical geared head assemblies, thereby entailing a time consuming and complex xe2x80x9cchange-outxe2x80x9d operation, or a separate camera assembly for those unique shots.
Various prior art systems have been developed for providing remotely controlled camera systems, particularly for ensuring repeatable shots and for permitting hazardous shoots without placing a camera operator in harm""s way. For example, U.S. Pat. No. 4,673,268 discloses a remote camera operation system comprising pan and tilt tables which are each actuatable by respective stepper motors. These tables may be computer controlled for repeatable shot sequences. However, this system is not adaptable for use with existing gear heads.
U.S. Pat. No. 4,720,805 discloses a computer-controlled camera system for controlling pan and tilt motors remotely using a digitizing tablet. However, again, this system is not adaptable for use with existing gear heads.
U.S. Pat. No. 4,847,543 discloses a remote-controlled camera system which uses control handles similar to those used in certain manual systems to actuate pressure transducers, which convert the movements of the handles initiated by the camera operator to voltage signals for actuating pan and tilt motors at the camera. The purpose of this arrangement is to facilitate repeatability of camera operation. This is not a remote system, but rather requires the operator to be located at the camera location.
U.S. Pat. No. 5,220,848 discloses a remote camera operation system wherein handwheels are used to operate a prior art cine head, which has a video monitor instead of a camera mounted thereon. Sensors transmit signals to a central control unit, based upon movements initiated by the camera operator on the handwheels, thereby actuating step or stepless actuator head motors. This system is disadvantageous, however, in that it is a complex customized approach not readily adaptable for quick change-out and use with existing gear heads.
Therefore, it would be highly desirable to have a geared head assembly which is directly adaptable to existing geared heads, is simple and quick to change out, affords a substantially greater number of mechanical gear ratios to select from, in order to provide the camera operator with an increased range of pan and tilt speeds, is programmable to provide selectable soft stops in both the pan and tilt axes, and is capable of recording a complex move so that it can be repeated precisely as many times as desired.
The present invention solves the aforementioned problems by providing a two-axis or three-axis digitally controlled microprocessor for remotely controlling an existing manually operated geared head. Because of the digital technology, the camera operator has full precise control of the geared head from a remote distance, as if he or she were physically behind the geared head personally.
Additionally, by utilizing the inventive system""s electronics, the operator has, in one preferred embodiment, ten gear ratios instead of the three gear ratios that typically exist in the prior art manual geared head. Also, three out of the ten speeds are matched with the standard geared head to emulate standard gearing on conventional geared heads. The additional seven gear ratios give the camera operator the ability to control the geared head speed by increasing or decreasing the speed from conventional choices.
Another advantage of the present invention permits the camera operator to set four predetermined soft stop positions, in one preferred embodiment. With the ability to set soft stop positions, the camera operator is guaranteed that he will never exceed the final position on either axis. For example, if a stunt person jumps from a platform into a stunt safety bag, the camera operator will take the camera, find the final position, and mark that position before photographing it. During photography, the electronics remember precisely where the mark is, and ensure that the camera will stop at that predetermined mark. The aforementioned stops are xe2x80x9csoft stopsxe2x80x9d because, regardless of how fast the operator moves the camera, the device ensures that the camera comes to a very soft and gentle stop.
Still another important feature of the present invention is that, because a standard motion picture geared head is utilized, with its limited tilt capability, the mechanical limits positions on the tilt axis are calibrated and recorded. As a result, the tilt axis may be feathered and stopped before the geared head reaches its mechanical limits in the up and down position, thus creating a soft stop for the tilt axis.
The inventive system has the capability of being able to record the X/Y/Z position precisely and to precisely duplicate the same camera motion repeatedly. The system is very simple and ergonomically advantageous to operate. One single umbilical cable between the controller and the geared head provides the most necessary communication between the controller and the geared head and supplies power to the camera.
More particularly, in one aspect of the invention there is provided a system for remotely controlling geared heads for motion picture and electronic medium cameras. Advantageously, the system comprises an electronic interface for attachment to an existing geared head for a motion picture or electronic medium camera. The system additionally comprises a tilt motor assembly mechanically attachable to the geared head and electronically attachable to the electronic interface, and a pan motor assembly which is also mechanically attachable to the geared head and electronically attachable to the electronic interface. A control console is electronically attachable to the electronic interface, which control console comprises a tilt motor input control and a pan motor input control.
In order to provide the remote operational capabilities of the inventive system, the control console is physically spaced from the geared head when the system is in an operating configuration.
In a preferred embodiment of the invention, the system further comprises a record/playback module, as well as a video monitor for use with the control console. The tilt motor input control and the pan motor input control each comprise a handwheel, preferably the handwheels which were originally attached to the geared head. This is advantageous in order to minimize any adaptations necessary on the part of the camera operator. The tilt motor assembly comprises a shaft for engagement with the tilt drive gear mechanism of the existing geared head, while the pan motor assembly comprises a shaft for engagement with the pan drive gear mechanism of the existing geared head.
In another aspect of the invention, there is provided an apparatus for electronically controlling geared heads for motion picture and electronic medium cameras, which comprises a tilt motor assembly attached to the geared head and a pan motor assembly attached to the geared head. Additionally, the apparatus comprises a system for establishing soft stops for limiting the pan and tilt travel of the geared head, which comprises software and a plurality of control inputs for actuation by an operator. A plurality of control inputs are disposed on a control panel and each of the control inputs operates to establish a soft stop for the geared head in one direction of travel. The soft stops are established by first moving the geared head to desired travel limits so that the computer software learns those limits.
In yet another aspect of the invention, there is provided a system for controlling geared heads for motion picture and electronic medium cameras, which comprises a geared head for controlling the movement of a camera attached thereto in the pan and tilt directions. A tilt motor assembly and a pan motor assembly are each attached to the geared head. Additionally, a control console is attached to the tilt motor assembly and the pan motor assembly. The control console is physically spaced and separate from the geared head and comprises a tilt motor input control and a pan motor input control.
In another aspect of the invention, there is disclosed a method of converting an existing manual geared head for a motion picture or electronic medium camera to a remotely controlled motorized gear head. The method comprises steps of replacing manual control inputs for pan and tilt gear mechanisms in the existing geared head with motorized control inputs, and a further step of attaching a control console to the motorized control inputs.
In still another aspect of the invention, there is disclosed a method of setting soft stops for limiting the range of motion of geared heads for motion picture and electronic medium cameras in the pan and/or tilt directions. The inventive method comprises a step of moving the geared head to its desired final position in any direction while depressing a soft stop control switch corresponding to that direction, and a further step of memorizing the desired final position using software adapted for such a purpose.